Baba <raoul...@gmail.com> writes: > Level: beginner > > I would like to know how to approach the following Fibonacci problem: > How may rabbits do i have after n months? > > I'm not looking for the code as i could Google that very easily. I'm > looking for a hint to put me on the right track to solve this myself > without looking it up.
fib(n) = fib(n-1) + fib(n-2), so you need the two previous values to compute the next one (that's the main difference between fibonacci and factorial). So here is a hint: instead of computing only fib(n), compute a pair (fib(n),fib(n-1)). It now becomes a problem very similar to factorial: for instance, what's (fib(7),fib(6)) if you have the values of (fib(6),fib(5))? Now write a recursive function fib2(n) that returns the last two values. And a simple wrapper fib(n) that calls fib2(n) and returns the first element of the pair. -- Alain. -- http://mail.python.org/mailman/listinfo/python-list
